This herb has a long history of use for various eye problems. To its credit, researchers have found that this herb contains anthocyanoside flavonoids (anthocyanins)—potent antioxidants that exhibit a particular affinity for the eye and vascular tissues. These anthocyanosides have been found to enhance microcirculation to the eyes and strengthen the optical portion of the retina. Studies have shown that supplementing with a standardized extract of this herb can improve visual acuity and the ability to adapt to changes in ambient light, as well as enlarge visual field. Furthermore, this herb is a good source of the antioxidant bioflavonoid, quercetin. What is this herb?